Search results for "light"
showing 10 items of 3575 documents
The Use of Chromatographic Methods Coupled to Mass Spectrometry for the Study of Emerging Pollutants in the Environment.
2018
The consumption of compounds that improve the human health and wellness is increasing, and as a result, the residues of these substances reach the environment or food chain. For this reason, the scientific community is looking for new analytical methods that are more accurate and can detect the greatest number of compounds in different matrices. This manuscript compares different studies in abiotic and biotic matrices, where most of them (92%) uses Liquid Chromatography to separate the compounds. For the detection, most of the studies for both matrices uses, coupled to the chromatograph, a triple quadrupole mass spectrometer (50%) due to the precision to quantify the concentration of these …
Influence of coordinated traffic lights parameters on roadside pollutant concentrations
2009
Abstract The paper examines the effects of coordinated traffic lights on CO and C 6 H 6 roadside concentrations in an urban area of Palermo in Southern Italy. Traffic loop detectors and one pollution-monitoring are used to collect data for use in DRACULA traffic microsimulator software. CO and C 6 H 6 roadside concentrations associated with varying cycle and offset times of the coordinated traffic lights are estimated using a neural network. Two functions were set up describing the relations of pollutant concentrations in term of cycle and offset time.
Overview: On the transport and transformation of pollutants in the outflow of major population centres - Observational data from the EMeRGe European …
2022
Megacities and other major population centres (MPCs) worldwide are major sources of air pollution, both locally as well as downwind. The overall assessment and prediction of the impact of MPC pollution on tropospheric chemistry are challenging. The present work provides an overview of the highlights of a major new contribution to the understanding of this issue based on the data and analysis of the EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) international project. EMeRGe focuses on atmospheric chemistry, dynamics, and transport of local and regional pollution originating in MPCs. Airborne measurements, taking advantage of …
Status Mutu Kualitas Air Laut Pantai Maruni Kabupaten Manokwari
2017
Penelitian ini bertujuan untuk mengetahui konsentrasi Amonia, Nitrat dan Ortoposfat serta parameter lainnya yang tertera pada baku mutu air laut untuk biota laut dan mengetahui status mutu kualitas air laut dengan menggunakan metode Indeks Pencemaran (IP). Konsentrasi ammonia dan nitrat dari dua periode pengamatan dalam satu wilayah Pantai Maruni secara konsisten menunjukkan hasil yang melebihi nilai ambang batas baku mutu lingkungan, sedangkan ortofosfat pada semua titik sampling masih dibawah nilai ambang batas baku mutu lingkungan sesuai Keputusan Menteri Lingkungan Hidup No. 51 Tahun 2004 tentang Baku Mutu Air Laut. Status mutu kualitas air laut Pantai Maruni berdasarkan analisis Indeks…
Micelles of polyisobutylene-block-poly(methacrylic acid) diblock copolymers and their water-soluble interpolyelectrolyte complexes formed with quater…
2004
The micellization of ionic amphiphilic diblock copolymers, polyisobutylene-block-poly(methacrylic acid) (PIB-b-PMAA), with a constant degree of polymerization of the non-ionic block ðDPn ¼ 20Þ and various degrees of polymerization of the polyelectrolyte block ðDPn ¼ 100 – 425Þ was examined in aqueous media by means of fluorescence spectroscopy using pyrene as a polarity probe. The molar values of the critical micellization concentration (cmc) were found to be around 2 £ 10 26 mol/l, being nearly independent of the length of the polyelectrolyte block as well as pH (in the range 6 – 9) and ionic strength (# 0.5 M NaCl) while the specific cmc values varied from 20 to 100 mg/l. Small-angle neut…
Multi-functional hindered amine light stabilizers-functionalized carbon nanotubes for advanced ultra-high molecular weight Polyethylene-based nanocom…
2015
Hindered Amine Light Stabilizer (HAS) molecules have been covalently linked on the outer surface of multi-walled carbon nanotubes (CNTs), and the so-obtained multi-functional fillers (HAS-f-CNTs) have been compounded with Ultra High Molecular Weight Polyethylene (UHMWPE) to get composite films. The success of the grafting reaction of the HAS molecules has been confirmed through spectroscopic and thermo-gravimetric analyses. Morphological analyses reveal a segregated microstructure, in which CNT-rich channels surround the polymer domains. This morphology results in improved mechanical properties and appreciable electrical conductive features. More importantly, the addition of only 1 wt.% of …
A New Hyaluronic Acid Derivative Obtained from Atom Transfer Radical Polymerization as a siRNA Vector for CD44 Receptor Tumor Targeting
2015
Two derivatives of hyaluronic acid (HA) have been synthesized by atom transfer radical polymerization (ATRP), starting from an ethylenediamino HA derivative (HA-EDA) and by using diethylaminoethyl methacrylate (DEAEMA) as a monomer for polymerization. Both samples, indicated as HA-EDA-pDEAEMA a and b, are able to condense siRNA, as determined by gel retardation assay and resulting complexes show a size and a zeta potential value dependent on polymerization number, as determined by dynamic light scattering measurements. In vitro studies performed on HCT 116 cell line, that over express CD44 receptor, demonstrate a receptor mediated uptake of complexes, regardless of their surface charge.
Effect of Core-Crosslinking on Protein Corona Formation on Polymeric Micelles.
2021
Most nanomaterials acquire a protein corona upon contact with biological fluids. The magnitude of this effect is strongly dependent both on surface and structure of the nanoparticle. To define the contribution of the internal nanoparticle structure, protein corona formation of block copolymer micelles with poly(N-2-hydroxypropylmethacrylamide) (pHPMA) as hydrophilic shell, which are crosslinked-or not-in the hydrophobic core is comparatively analyzed. Both types of micelles are incubated with human blood plasma and separated by asymmetrical flow field-flow fractionation (AF4). Their size is determined by dynamic light scattering and proteins within the micellar fraction are characterized by…
Heparin-Based Nanocapsules as Potential Drug Delivery Systems
2015
Herein, the synthesis and characterization of heparin-based nanocapsules (NCs) as potential drug delivery systems is described. For the synthesis of the heparin-based NCs, the versatile method of miniemulsion polymerization at the droplets interface was achieved resulting in narrowly distributed NCs with 180 nm in diameter. Scanning and transmission electron microscopy images showed clearly NC morphology. A highly negative charge density for the heparin-based NCs was determined by measuring the electro-kinetic potential. Measuring the activated clotting time demonstrated the biological intactness of the polymeric shell. The ability of heparin-based NCs to bind to antithrombin (AT III) was i…
Estimation of Number-Average Molecular Weights of Copolymers by Gel Permeation Chromatography−Light Scattering
1996
The true number-average molecular weight, Mn, of copolymers is obtained by GPC coupled with a light-scattering detector even if the composition and therefore the refractive index increment varies with elution volume, provided slices taken are monodisperse with respect to molecular weight and composition. In contrast, only an apparent weight-average molecular weight, can be obtained by the conventional GPC−light scattering combination, even for a perfect chromatographic resolution. The errors in Mn associated with nonhomogeneous slices are estimated. Experimental data with mixtures of linear polystyrene and poly(methyl methacrylate) confirm these estimations and indicate that the error in Mn…